Rotational bearings are very well known in the art to provide an interface between a rotating structure and a contact surface. It is common to employ some type of pad or pads at the interface to optimize the interconnection between the bearing and the rotating structure and to transmit axial and/or radial forces, which may be accomplished through providing compliance within the bearing in those respective directions.
Load capacity is highly dependent on the pad interface in a bearing. It has been found that the interface may be optimized for better transmission of axial thrust forces by tilting the pads of a bearing or otherwise providing a compliant contact to reduce the amount of friction. Such increasing load capacity by reduced friction may be achieved by controlled hydroplaning. Typically, compliant arrangements include an array of fixed pads that are all tilted in a given rotational direction, such as a forward rotational direction. This is advantageous in that hydroplaning may be achieved.
In the prior art, it is well know that the very low viscosity of gas lubricant causes a gas thrust bearing to run at very thin film thickness to support thrust load generated in the rotating machines. However, a known drawback is that any misalignments or geometrical tolerances (such as warping) of rotating shaft collar and/or bearing surface negatively impacts the thrust load capability of the bearing. This runs counter to the continual desire to increase load capacity of the bearing. Further, any thermal distortion or deflection of the shaft collar and/or \bearing surface during operation is another factor that influences the thrust load capability of the bearing.
A spiral grooved thrust bearing typically has the best load capability among all hydrodynamic gas thrust bearings. However, the fact that negative damping may be generated at certain operating conditions (combination of speed and thrust load) is a major drawback of such spiral groove thrust bearings. This behavior of spiral grooved gas thrust bearings is another factor that undesirably limits load capacity of a bearing.
There is a need for a compliant bearing with increased load capacity.
There is a need for a thrust bearing with axial compliance.
There is a need for a compliant bearing with axial damping.
There is a need for a compliant bearing that is more stable than prior art compliant bearings.
There is a need for a thrust bearing with some type of axial compliance to help maintain a proper film thickness by allowing deformation and/or tilt of compliant bearing surface as need of rotating runner surface.
There is a need to provide axial compliance of a thrust bearing to increase the overall load capacity of the bearing.
There is a need to monitor the performance and/or operating conditions on any compliant bearing, radial, axial, or otherwise.
DETAILED DESCRIPTION—LISTING OF ELEMENTSELEMENT DESCRIPTIONELEMENT #Shaft 4Shaft collar 6Groove thrust bearing10Pad thrust bearing12Main body14Multi-compliant bearing16Bearing surface20Groove pattern22First bearing surface spring24Second bearing surface spring26Interstitial area28Damping material29Bearing pad30Bearing pad interface32Pad radial spring34Pad axial spring36Interstitial area38Bearing pad30'Bearing pad interface32'Post34'Post base34a'Sensor web40First sensor42Second sensor42aThird sensor42bFourth sensor42c